This invention relates to internal combustion engines. More particularly, it relates to such engines including positive crank case ventilation valves and to valve constructions for positive crank case ventilation valves.
Ever-increasing concern for air pollution has, in recent years, seen mandatory requirements for positive crank case ventilation valves in internal combustion engines. Typically, such valves are employed in a system wherein noxious fumes within the crank case are cycled to the clean air side of the air intake for the engine so as to be drawn into the engine and consumed during the usual combustion process when gas pressure in the crank case reaches some predetermined value. Heretofore, such valves have typically employed springs as part of their working mechanism to assist in controlling the opening and closing of the valve in response to changes in pressure within the crank case.
In general, such systems have been satisfactory, but owing to the employment of elements such as springs, there is the difficulty of achieving good uniformity in response from one valve to the next. There is also the possibility that, after extended use, and substantial cyclic flexure of the spring, the same may fail to thereby interfere with proper operation of the system.